1. Field of the Invention
The present invention generally involves sensors. More specifically, the present invention relates to wireless detection of area changes.
2. Description of Related Art
In recent years, a growing concern over environmental responsibility and viability has prompted various measures to reduce energy consumption and ensuing costs. In commercial and residential settings, one solution is the use of a sensor for detecting certain environmental conditions and initiating a adjustment of an electrical load device (i.e., electricity-consuming device) in response to the detected condition(s). For example, some building installations (e.g., offices) have installed occupancy sensors to detect motion in a given location. An occupancy sensor wired to a lighting fixture, for example, may detect movement or lack of movement in a particular room and cause the lighting fixture to turn on or off in response. Such sensor may initiate such response by communicating with an actuator or switch of the electrical load device.
Issues with such a scheme may include inflexibility and difficulty and expense associated with retrofitting for changing and/or growing installations. For example, a sensor may have to be rewired when electrical load devices are added, removed, or relocated and when user preferences change. Such situations may require rewiring and reconfiguration of sensor settings to reflect the new arrangement and requirements thereof.
Presently available sensors generally operate by transmitting a signal over a wired connection to an actuator (e.g., relay, power pack), which provides for control of an electrical load. Such presently available sensors are not configured for wireless communication. As such, those sensors are limited to certain types of signals, such as those indicating detection of motion, or lack thereof.
Another challenge for such sensors in a conventional lighting control system is that such sensors are usually mounted at an elevated position (e.g., ceiling, wall). As such, the sensor may be remote from various parts of a location. For example, in an office, it may be desirable to determine the light level around a work surface (i.e., desk). Because the sensor is mounted in an elevated position, the sensor may end up measuring reflected light from both the target surface, as well as from the surrounding environment. As such, the sensor reading is inaccurate, thereby possibly resulting in inappropriate responses.
Other issues may include inflexibility to changing requirements of the occupants. For example, an occupant may require different lighting response on weekdays than he/she does on weekends. Sensors that are not sensitive enough may not detect fine movements (e.g., typing at a desk), and sensors that are over-sensitive may detect movement outside a door or window, resulting in responses that inappropriate to the actual situation in an area.
There is therefore a need in the art for improved methods and systems for wireless sensing.